Abstract: A secondary battery includes an electrode body having an electrode plate, a rectangular exterior body, a sealing plate, an electrode terminal, a first current collector arranged between the electrode body and the sealing plate and connected to the electrode terminal, a second current collector arranged between the electrode body and a side wall of the rectangular exterior body and connected to the first current collector, and a tab group formed such that multiple electrode tabs extending from the electrode plate toward the side wall are stacked on each other and connected to the second current collector. The tab group is connected to the second current collector, and is bent in parallel with the side wall. The curvature radius of a first rounded portion of a base portion of each tab is greater than the curvature radius of a second rounded portion of a tip portion of each tab.

Abstract: According to the present disclosure, a secondary battery capable of inhibiting precipitation of metallic lithium is provided. The secondary battery disclosed herein includes a flat wound electrode body. A positive electrode starting end portion inside the electrode body has a first region extending along a flat portion of the electrode body. On the other hand, a negative electrode starting end portion inside the electrode body has a second region extending along the flat portion, a folded portion folded back from an end portion of the second region, and a third region extending from an end portion of the folded portion. In addition, the electrode body has an electrode starting end stacked portion in which the first region, the second region, and the third region overlap. According to such a configuration, it is possible to prevent a partial pressing failure from occurring and inhibit the precipitation of metallic lithium.

Abstract: A battery disclosed herein includes: an exterior body including a bottom wall and an opening facing the bottom wall; a sealing plate sealing the opening of the exterior body; and one or a plurality of wound electrode bodies, in which a band-shaped positive electrode including a positive electrode active material layer and a band-shaped negative electrode including a negative electrode active material layer are laminated via a band-shaped separator and are wound around a winding axis. A length of the positive electrode active material layer is 15 cm or more in a winding axis direction of the wound electrode body. A plurality of winding stop tapes are attached to an outer surface of the wound electrode body at intervals in the winding axis direction.

Abstract: A battery electrode which is one example of an embodiment is provided with a core and an active material layer disposed on the surface of the core. The core has a based part where the core surface is covered by the active material layer and a tab part projecting from the based part. Notches are formed on the core from the base of the tab part to the base part, or at positions where the base part adjoins the tab part. The edge of each notch is formed from a first curve comprising a first arc and either a second curve comprising a second arch having a smaller curvature than the first arc or a straight line. This allows a battery electrode to be provided such that the occurrence of cracks at the base of the tab part of the core and in the vicinity thereof can be sufficiently suppressed.